What was found
ORD - FLT 631 - DURING CRUISE AT FL 370, FLIGHT ATTENDANTS NOTICED A STRONG ODOR WITH SMELL OF SMOKE IN AFT CABIN. SMELL DISSIPATED AFTER A FEW MINUTES WITH NO REOCCURRENCE FOR THE REMAINDER OF THE FLIGHT. FLIGHT LANDED ORD WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED BOTH COALESCER BAGS, RAN PACKS WITH ENGINES AND APU WITH NO ODOR OR SMOKE NOTED. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)